First factor out the 2 to get 2(x^4-10x^2-39)
Replace any x^2 value with the variable a, so x^4 becomes a^2 because x^2 squared is x^4. You just do this to take the place of any x^2 s to make it easier, if that makes sense. So 2(a^2-10a-39). Then you can do regular factoring. 3 and -13 multiply to become -39, and 3-13=10. So The equation would become \[2(a+13)(a-3)\] Then change the a's back into x^2. So the answer is \[2(x ^{2}+3)(x ^{2}-13)\] So the answer is the second one.

You can check your work by multiplying the factors back together using either the box method or FOIL. \[2(x ^{4}-13x ^{2}+3x ^{2}-39)\]Combine like terms to get \[2(x ^{4}-10x ^{2}-39)\]Then distribute the 2 \[2x ^{4}-20x ^{2}-78\]You know your answer is correct if it is the same as the original equation.